GSD – Assimilation and Modeling Branch
35th Conference on Radar Meteorology30 September 2011
Analysis of forecast improvement from radar-data assimilation
within RUC, Rapid Refresh and HRRR models
Steve Weygandt, Curtis Alexander, Ming Hu, Patrick Hofmann,
Eric James, Haidao Lin, Tanya Smirnova, David Dowell,
Stan Benjamin, John Brown
Hourly Updated NOAA NWP Models
13km Rapid Refresh
(mesoscale)
13km RUC (mesoscale)
3km HRRR (storm-scale)
RUC – current oper Model, new 18h fcst every hour
High-Resolution Rapid Refresh Experimental 3km nest inside RR, new 15-h fcst every hour
Rapid Refresh (RR) replaces RUC at NCEP in 2011 WRF, GSI with RUC features
NOAA/ESRL/GSD/AMB ModelsModel Domain Grid
PointsGrid
SpacingVertical Levels
Vertical Coordinate
Height Lowest Level
Pressure Top
RUC CONUS 451 x 337 13 km 50 Sigma/ Isentropic 5 m ~50 mb
RR North America 758 x 567 13 km 50 Sigma 8 m 10 mb
HRRR CONUS 1799 x 1059 3 km 50 Sigma 8 m 85 mb
Model Run at: Time-Step Forecast Length Initialized Boundary
ConditionsRun Time
# of CPUs
RUCNCEPoper
18 s 18 hrs Hourly (cycled) NAM ~25 min 32
RR GSD, EMC 60 s 18 hrs Hourly (cycled) GFS ~25 min 160
HRRR GSD 15-20s 15 hrs Hourly (no-cycle)
RUC(RR --Apr 11) ~50 min ~1000
Models at NOAA/ESRL/GSD/AMB
Model Assimilation DFI Microphysics Radiation Convection PBL LSM
RUC RUC-3DVAR Yes w/radar Thompson RRTM/Dudhia G3 MYJ RUC
RR GSI Yes w/radar Thompson RRTM/Goddard G3 MYJ RUC
HRRR None:RUC / RR I.C. No Thompson RRTM/Goddard None MYJ RUC
RR physics behavior similar to RUC – good for aviation, convective environment , surface and
sensible weatherNCEP upgrade from RUC to RR will provides moreadvanced model and analysis components
- WRF-ARW: advanced numerics, non-hydrostatic- GSI: advanced satellite DA, 4DVAR/EnKF development- Both community-based, ongoing code contributions
• “Radar-DFI” assimilation procedure in NCEP RUC since Nov. 2008 improved fcsts precip systems
• Radar-DFI in GSD RR since 2008, RR to replaceRUC at NCEP late 2011
• Hourly CONUS HRRR nest in RUC since 2008 HRRR benefitted from RUC radar-DFI
• HRRR switched to run as nest within RR (with RR radar-DFI) in April 2011.
• HRRR run in real-time to support CoSPA, SPC, NWS regions, renewable energy
Quantify radar DFI impact on RUC, RRand HRRR nests for summer-time convection
Establish baseline for more sophisticated radar assimilation efforts
Background / Goals
Rawinsonde (balloons)Wind Profilers (405 MHz, 915 MHz)
RASS virtual temperaturesVAD winds (WSR-88D radars)
Aircraft (ACARS, TAMDAR) Surface (METAR , Buoy,
Mesonet )Precipitable water (GPS, GOES,
SSM/I)GOES cloud-drift winds
GOES cloud-top pressure/tempRadar reflectivity, lightning
Ship reports/dropsondesSatellite radiances (RR)
Rapid Refresh Hourly Cycle / Observations
1-hrfcst
1-hrfcst
1-hrfcst
11 12 13Time (UTC)
AnalysisFields
3DVAR
Obs
3DVAR
Obs
Back-groundFields
Hourly updating using all available observations
Data types used
Spring 2011 Hourly HRRR Initialization from RR
HourlyRR
LateralBoundaryConditions
Interp to 3 km grid
HourlyHRRR
15-h fcst
Initial Condition
Fields
11 z 12 z 13 z
Time (UTC)
AnalysisFields
3DVAR
Obs
3DVAR
Obs
Back-groundFields
18-h fcst 18-h fcst
1-hr
fcst
DDFI DDFI
1-hr
fcst
18-h fcst
1-hr
fcst
Interp to 3 km grid
15-h fcst
Use 1-h old LBC
to reducelatency
Use most recent IC (post-DFI)
to get latest radar info
Reduced Latency:
~2h for 2011
Digital Filter-based reflectivity assimilationinitializes ongoing precipitation regions
Radar reflectivity assimilation
Forward integration,full physics with radar-based latent heating
-20 min -10 min Initial +10 min + 20 min
RUC / RR HRRR model forecast
Backwards integration, no physics
Initial fields with improved balance, storm-scale circulation
Digital Filter-based reflectivity assimilationinitializes ongoing precipitation regions
Radar reflectivity assimilation
Forward integration,full physics with radar-based latent heating
-20 min -10 min Initial +10 min + 20 min
RUC / RR HRRR model forecast
Backwards integration, no physics
Initial fields with improved balance, storm-scale circulation
+ RUC/RR Convection suppression
No precipitation hydrometeor specification*
psfct
Diabatic Digital Filter InitializationReduce noise in RUC and Rapid Refresh
No
ise
pa
ram
ete
r
Rapid Refresh (GSI + ARW) reflectivity assimilation example
Low-levelConvergence
Upper-levelDivergence
K=4 U-comp. diff (radar - norad)
K=17 U-comp. diff
(radar - norad)
NSSL radar reflectivity
(dBZ)
14z 22 Oct 2008Z = 3 km
• No cycling on the 3-km HRRR grid, must “spin-up storms within each run followed by accelerated storm evolution
“match” with real-world evolution depends on stage of actual storm evolution
• How effective is cycled “radar-DFI” procedure applied on mesoscale grid?-- for mesoscale “parent” grid?-- for storm-scale “child” grid?
• How does parameterized convection on parent grid impact evolution of storm-scale model?
• Similarities / difference RUC-HRRR vs. RR-HRRR?
Issues / Questions
• To what degree is storm evolution controlled by mesoscale vs. storm-scale forcing?
Highly variable based on regime, but mesoscale forcing is very significant
-- We don’t accurately observe or predict mesoscale
mesoscale forcing == high predictability
-- Strong mesoscale forcing does imply reduced impact from radar data assimilation, unlessassimilated radar data improves mesoscale fields
(cold pools, low-level wind fields, etc.)
Issues / Questions
R/T-Retro Experiment Weather
11 12 13 14 15 16 17 18 19 20 21
RRAug 2011
RUCRR -- HRRR
RUC -- HRRR NO radarassimilation
YES radarassimilation
REAL-TIME
RETROSPECTIVE
R/T-Retro Experiment Weather
11 12 13 14 15 16 17 18 19 20 21
RRAug 2011
RUCRR -- HRRR
RUC -- HRRR NO radarassimilation
YES radarassimilation
REAL-TIME
RETROSPECTIVE
R/T-Retro Experiment Weather
11 12 13 14 15 16 17 18 19 20 21
RR -- HRRRAug 2011
RUC -- HRRRRR -- HRRR
RUC -- HRRR NO radarassimilation
YES radarassimilation
REAL-TIMEEvery 2 hoursEvery 1 hour
RETROSPECTIVE
R/T-Retro Experiment Weather
11 12 13 14 15 16 17 18 19 20 21
RR -- HRRRAug 2011
RUC -- HRRRRR
RUC NO radarassimilation
YES radarassimilation
REAL-TIMEEvery 2 hoursEvery 1 hour
RETROSPECTIVE
R/T-Retro Experiment Weather
11 12 13 14 15 16 17 18 19 20 21
RR -- HRRRAug 2011
RUC -- HRRRRR -- HRRR
RUC -- HRRR NO radarassimilation
YES radarassimilation
REAL-TIMEEvery 2 hoursEvery 1 hour
RETROSPECTIVE
R/T-Retro Experiment Weather
11 12 13 14 15 16 17 18 19 20 21
RR -- HRRRAug 2011
RUC -- HRRRRR -- HRRR
RUC -- HRRR NO radarassimilation
YES radarassimilation
REAL-TIMEEvery 2 hoursEvery 1 hour
00z 13 Aug
02z 12 Aug
RETROSPECTIVE
R/T-Retro Experiment Weather
11 12 13 14 15 16 17 18 19 20 21
RR -- HRRRAug 2011
RUC -- HRRRRR -- HRRR
RUC -- HRRR NO radarassimilation
YES radarassimilation
REAL-TIMEEvery 2 hoursEvery 1 hour
00z 13 Aug
02z 12 Aug
22z 13 Aug
RETROSPECTIVE
R/T-Retro Experiment Weather
11 12 13 14 15 16 17 18 19 20 21
RR -- HRRRAug 2011
RUC -- HRRRRR -- HRRR
RUC -- HRRR NO radarassimilation
YES radarassimilation
REAL-TIMEEvery 2 hoursEvery 1 hour
00z 13 Aug
02z 12 Aug
22z 13 Aug
14z 14 Aug
00z 15 Aug
RETROSPECTIVE
R/T-Retro Experiment Weather
11 12 13 14 15 16 17 18 19 20 21
RR -- HRRRAug 2011
RUC -- HRRRRR -- HRRR
RUC -- HRRR NO radarassimilation
YES radarassimilation
REAL-TIMEEvery 2 hoursEvery 1 hour
00z 13 Aug
02z 12 Aug
22z 13 Aug
14z 14 Aug
00z 15 Aug
04z 19 Aug
RETROSPECTIVE
20z 19 Aug
80-km
valid (GMT)valid (EDT)
00 02 04 06 08 10 12 14 16 18 20 22 8p 10p 12 2a 4a 6a 8a 10a 12 2p 4p 6p
“neighborhood” verification of 6-hforecasts from 3-km HRRR
verification:10 June – 26 Sept 2010
40-km
20-km
25 dBZ6-h fcst
3-km
80-km
valid (GMT)valid (EDT)
00 02 04 06 08 10 12 14 16 18 20 22 8p 10p 12 2a 4a 6a 8a 10a 12 2p 4p 6p
“neighborhood” verification of 6-hforecasts from 3-km HRRR
verification:10 June – 26 Sept 2010
ConvectiveInitiation
period
40-km
20-km
25 dBZ6-h fcst
3-km
80-km
valid (GMT)valid (EDT)
00 02 04 06 08 10 12 14 16 18 20 22 8p 10p 12 2a 4a 6a 8a 10a 12 2p 4p 6p
“neighborhood” verification of 6-hforecasts from 3-km HRRR
verification:10 June – 26 Sept 2010
ConvectiveInitiation
period
40-km
20-km
25 dBZ6-h fcst
3-km
ConvectiveDecayperiod
80-km
valid (GMT)valid (EDT)
00 02 04 06 08 10 12 14 16 18 20 22 8p 10p 12 2a 4a 6a 8a 10a 12 2p 4p 6p
“neighborhood” verification of 6-hforecasts from 3-km HRRR
verification:10 June – 26 Sept 2010
ConvectiveInitiation
period
40-km
20-km
25 dBZ6-h fcst
3-km
ConvectiveDecayperiod
R/T-Retro Experiment Configuration
Mostly compare RUC-HRRR vs. RR-HRRR (w/ and w/o radar)
Also compare RUC and RR (w/ and w/o radar assimilation)
Reflectivity and precipitation verification (also upper-air, surface)
RUC RR
NO radar assim
YES radar assim
also RUC RR HRRR HRRR
R/T-Retro Experiment Configuration
Mostly compare RUC-HRRR vs. RR-HRRR (w/ and w/o radar)
Also compare RUC and RR (w/ and w/o radar assimilation)
Reflectivity and precipitation verification (also upper-air, surface)
RUC RR
NO radar assim
YES radar assim
also RUC RR HRRR HRRR
Initial Hydrometeor specification:RUC – No precipitation hydrometeor specification0-h RUC-HRRR reflectivity from 1-h RUC explicit hydrometeorsRR – Specify snow hydrometeors only0-h RR-HRRR reflectivity from 1-h RR explicit HMs + radar snow
13-km Eastern USMatched comparison
2 X 12 hr fcstvs. CPC 24-h analysis
11 – 21 Aug. 2011All init times
Rapid Refreshvs. RUC
PrecipitationVerification
RUC radar
| | | | | | | 0.01 0.10 0.25 0.50 1.00 1.50 2.00 in.
CSI(x 100)
RUC no radar
RR radar
RR no radar
| | | | | | | 0.01 0.10 0.25 0.50 1.00 1.50 2.00 in.
bias(x 100)
100(1.0)RUC
radarRUC
no radar
RR radarRR
no radarRadar assim
improves precip CSIs scores,
but also increases bias
Threshold
| | | | | | | 0-h 2-h 4-h 6-h 8-h 10-h 12-h
25 dBZ 13-kmEastern USMatched Comparison12,13,14,19 Aug. 2011All init times
“parent” vs. “child”ReflectivityVerification
| | | | | | | 0-h 2-h 4-h 6-h 8-h 10-h 12-h
CSI(x 100)
RR-HRRR radar
RR-HRRR no radar
3-km fcsts improve upon parent 13-km
forecasts radar assim
adds skill at both 13-km and 3-km
RR radar RR
no radar
Forecast Lead Time
RUC-HRRR radar
RUC-HRRR no radar
RUC radar RUC
no radar
CSI(x 100)
RUC-HRRRvs. RR-HRRR ReflectivityVerification
RUC-HRRR radar
CSI(x 100)
RUC-HRRR no radar
RR-HRRR radar
RR-HRRR no radar
bias(x 100)
100(1.0)
Radar assim improves precip CSIs scores,
but also increases bias
| | | | | | | 0-h 2-h 4-h 6-h 8-h 10-h 12-h
Forecast Lead Time
| | | | | | | 0-h 2-h 4-h 6-h 8-h 10-h 12-h
Eastern US, 25 dBZ 13-km CSI3-km biasMatched Comparison12,13,14,19 Aug. 2011All init times
RUC-HRRR radar
RUC-HRRR no radar
RR-HRRR radar
RR-HRRR no radar
| | | | | | | 0-h 2-h 4-h 6-h 8-h 10-h 12-h
RUC-HRRR radar
RUC-HRRR no radar
RR-HRRR radar
RR-HRRR no radar
| | | | | | | 0-h 2-h 4-h 6-h 8-h 10-h 12-h Forecast Lead TimeForecast Lead Time
| | | | | | | 0-h 2-h 4-h 6-h 8-h 10-h 12-h
| | | | | | | 0-h 2-h 4-h 6-h 8-h 10-h 12-h
18z inits 00z inits
06z inits 12z inits
CSI for different Initialization times
00z 06z 06z 12z
12z 18z 18z 00z
18z
06z
00z
12z
RRHRRR
RADAR
NSSL mosaic
RRHRRR
no radar
RUCHRRR
RADAR
RUCHRRR
no radar
01z 13 Aug 201100z
init
RRHRRR
RADAR
NSSL mosaic
RRHRRR
no radar
RUCHRRR
RADAR
RUCHRRR
no radar
01z 13 Aug 201100z
init0h 2h 4h 6h 8h
CSI scores
01z 13 Aug 2011
RRHRRR
RADAR
NSSL mosaic
RRHRRR
no radar
RUCHRRR
RADAR
RUCHRRR
no radar
00z + 1 hr fcsts
00z 13 Aug 2011
NSSL mosaic
RUCHRRR
RADAR
00z initialization
00z 13 Aug 2011
NSSL mosaic
RUCHRRR
RADAR
00z initialization
RRHRRR
no radar
RUCHRRR
no radar
RRHRRR
RADAR
00z 13 Aug 2011
NSSL mosaic
RUCHRRR
RADAR
RRHRRR
no radar
RUCHRRR
no radar
RRHRRR
RADAR
00z initialization
00z 13 Aug 2011
NSSL mosaic
RUCHRRR
RADAR
RRHRRR
RADAR
RUCHRRR
no radar
RRHRRR
no radar
00z initialization
01z 13 Aug 2011
RRHRRR
RADAR
NSSL mosaic
RRHRRR
no radar
RUCHRRR
RADAR
RUCHRRR
no radar
00z + 1 hr fcsts
02z 13 Aug 2011
RRHRRR
RADAR
NSSL mosaic
RRHRRR
no radar
RUCHRRR
RADAR
RUCHRRR
no radar
00z + 2 hr fcsts
04z 13 Aug 2011
RRHRRR
RADAR
RRHRRR
no radar
RUCHRRR
RADAR
RUCHRRR
no radar
00z + 4 hr fcsts
NSSL mosaic
06z 13 Aug 2011
RRHRRR
RADAR
RRHRRR
no radar
RUCHRRR
RADAR
RUCHRRR
no radar
00z + 6 hr fcsts
NSSL mosaic
• “Radar-DFI” in mesoscale model improves mesoscale model precipitation and nested storm- scale reflectivity forecasts
• Results very similar for RUC-HRRR, RR-HRRR
• Radar-DFI focuses mesocale convective areas, suggestion of indirect convective suppression
• Radar data impact quite case dependent,strong diurnal aspect with little retention across mid-day convective minimum
• RR-HRRR convects more easily than RUC-HRRR, HRRR has difficulty propagating leading convective lines for both RR and RUC fields, especially for strongly capped environments
• Limitations to non-cycled 3-km forecasts
Conclusions and future work